1. Field of the Invention
The present invention relates to a voice monitoring system for subscribers handled by time division switches in a telephone network, particularly for subscribers accommodated by remote (site) local equipment.
2. Description of the Related Art
A previously presented voice monitoring system for subscribers handled by telephone network's time division switches was like the one shown in FIG. 3 (Japanese Published Unexamined Patent Application No. Sho 59-165555). Summarizing this previous system by referring to FIG. 3 is as follows.
Assume that a subscriber 1 is placed in the speech state, using a trunk 3. Given that a request for monitoring for the trunk 3 is issued from a monitor console 6 in this case, an activation signal is first transmitted from the monitor console 6 to a trunk for monitor console 7. When a time division switch of the telephone network detects the activation signal received by the trunk for monitor console 7, it makes the connection between the trunk for monitor console 7 and an MF receiver 8 via a path 10. When the monitor console 6 is thus connected to the MF receiver 8, it transmits a circuit number in the trunk 3 for which it desires monitoring as number information to the MF receiver 8. Then, the time division switch of the telephone network releases the path 10 that was used for the connection between the trunk for monitor console 7 and the MF receiver 8, selects an idle trunk for three party speech 5 and establishes the connection between monitor connection paths 11, 12, and 13 to complete the connection for the requested monitoring.